Driving his backup, Keselowski raced to his series-leading third victory of the year Saturday night, grabbing the lead with 55 laps remaining and holding off all challengers in the NASCAR Sprint Cup race at Kentucky Speedway.

"It wasn't the newest car we got, but it runs," Keselowski said.

The 28-year-old from Rochester Hills, Mich., picked up his seventh win in his five years on the circuit. He won earlier this year at Bristol and Talladega. He gave all the credit for the latest victory to his team.

"They put together a backup car from last year in 100-degree heat in one hour's time to get me back on the track," he marveled.

Kasey Kahne rode a late surge to second place, 4.399 seconds back of the winner.

So well was Keselowski running that Kahne, despite his fast finish, knew he needed help to catch him.

"I just hoped he'd run out of gas," Kahne said, grinning. "No way I was catching him. We had stopped (for a fill-up) and I was hoping he'd shut down."

Keselowski had just enough fuel to finish.

Crew chief Paul Wolfe called the quick turnaround in cars "probably the toughest weekend our team has ever had up to this point."

"I'm just really proud of everybody on this team, to pull out a backup car after having that crash on the first lap on the track just says a lot about all these guys," he said. "To be able to have a backup car that is capable of winning a race says a lot."

While registering his 16th career top-five finish in the 267-lap race, Keselowski, who led for 68 total laps, ended a lull over the past four starts where he had failed to crack the top 10.

He was driving his backup car after slamming the right side of his top car into the wall in the wake of a collision with Juan Pablo Montoya during practice Friday.